Inspection Procedure A-9: When the ignition switch is turned to the ON position with the lighting switch at the OFF or TAIL position, the headlamps will illuminate briefly.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM


If the headlamps illuminate briefly when the ignition switch is turned to the ON position with the lighting switch at the OFF or TAIL position, room lamp fuse in the junction block is blown (pulled off).

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Check room lamp fuse.
Check room lamp fuse in the junction block is blown or pulled off.

Q. Is the check result normal?
Go to Step 2.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - Inspection service points for a blown fuse ).

STEP 2. Check that the headlamps operate.
Check that the low-beam and high-beam headlamps work normally.

Q. Is the check result normal?
Go to Step 3.
Follow Inspection Procedure A-1: None of the low-beam headlamps illuminate (Refer to ) and Inspection Procedure A-2: None of the high-beam headlamps illuminate (Refer to ). Then go to Step 4.

STEP 3. M.U.T.-III diagnosis code.
Check if the ETACS-ECU sets a diagnosis code.

Q. Is the diagnosis code set?
Diagnose the ETACS-ECU (Refer to ). After the repair, go to Step 4.
Go to Step 4.

STEP 4. Voltage measurement at column switch connector.
(1)Disconnect the connector, and measure at the wiring harness-side connector.
(2)Measure the voltage between the column switch connector (power supply terminal) and the body earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 6.
Go to Step 5.

STEP 5. Check of short to power supply, and open circuit in power supply line between column switch connector and junction block connector.

Q. Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.

STEP 6. Retest the system.
Check whether the headlamps illuminate briefly when the ignition switch is turned to the ON position with the lighting switch in the OFF or TAIL position.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the column switch (Refer to ).